Daikin Industries, Ltd.

Ideal Star Inc.

Toho Kasei Co., Ltd.

Osaka University

Daiki Industries, Ltd.

Tetsuhiro Kodani

Takashi Kanemura

Eri Mukai

Takayuki Araki

Meiten Kou

Saori Sakami

Shinya Bitou

Meiten Koh

Yuuki Kuwajima

Kwan-Young Han

Takaya Yamada

Arifumi Matsumoto

Kenji Omote

Yuji Imahori

Hiroji Ohigashi

Satoshi Shimizu

Susumu Kawato

Tsuyoshi Sekitani

Akinari Sugiyama

Takuji Ishikawa

Hisako Nakamura

Kouji Yokotani

Nobuyuki Komatsu

Tomoyuki Gotou

Takafumi Uemura

Mayuko Tatemichi

Shusuke Yoshimoto

Takeshi Hazama

Akio Higaki

Hiroyuki Sagami

Saori Inaba

Hyunsik Kim

Kenji Ishida

Shuichiro Kuwajima

Toshihisa Horiuchi

An object is to provide a piezoelectric film with good piezoelectricity. This object can be achieved by a piezoelectric film comprising a vinylidene fluoride/tetrafluoroethylene copolymer film and having a residual polarization amount of 40 mC/mor more.

Piezoelectric film having a vinylidenefluoride/tetrafluoroethylene copolymer film

An object of the present invention is to provide a vibration sensor in which the frequency dependence of the output is small. The present invention provides a vibration sensorcomprising: a support; an organic piezoelectric materialdeformably disposed in or on the support; and an electrodefor extracting an electrical signal generated by deformation of the organic piezoelectric material, the electrodebeing formed on the organic piezoelectric material, the organic piezoelectric materialcomprising a copolymer of vinylidene fluoride and one or more monomers copolymerizable with vinylidene fluoride.

Vibration sensor and piezoelectric element

The present invention relates to a pressure signal detection circuit and a pressure signal detection method in which a pyroelectric signal from a piezoelectric film is suppressed. More specifically, the pressure signal detection circuit receives input of an input signal from a piezoelectric film, differentiates the input signal for signal component analysis of the input signal, outputs the signal analysis value of the input signal based on the differential value, removes offset of the input signal by using the signal component analysis value, integrates the input signal, and outputs a pressure input signal value from which a heat input signal value is removed.

Circuit and method for detecting pressure signal with signal due to pyroelectricity in piezoelectric material being suppressed

The present invention addresses the problem of providing a bimorph-type piezoelectric film that is less susceptible to the influence of pyroelectric noise resulting from temperature changes, and that makes it possible to provide a pressure-sensitive sensor or the like. The present invention provides a bimorph-type piezoelectric film comprising a first pyroelectric film having piezoelectric anisotropy in an in-plane direction, and a second pyroelectric film having piezoelectric anisotropy in an in-plane direction, the first pyroelectric film and the second pyroelectric film being disposed in such a manner that their surfaces on which electric charges of the same polarity are generated by a temperature increase are each outward-facing.

Bimorph-type piezoelectric film

The present invention provides a film having excellent heat resistance and a small difference between the permittivity at low temperatures and the permittivity at high temperatures. The present invention provides a film having a relative permittivity of 8 or more at a frequency of 1 kHz at 30&#xb0; C., wherein the rate of change is &#x2212;8 to +8% as calculated from a relative permittivity A at a frequency of 1 kHz at 30&#xb0; C. and a relative permittivity B at a frequency of 1 kHz at 150&#xb0; C. according to the following formula:Rate of change(%)=()/100.

Film

An object of the present invention is to provide a bimorph piezoelectric film that enables the production of touch panels and the like that are less influenced by pyroelectric noise due to temperature change, and exhibit high transparency. The present invention provides a bimorph piezoelectric film comprising in sequence

A touch panel hardly affected by pyroelectric noise due to temperature includes a first pyroelectric material and a second pyroelectric material, and is capable of detecting press pressure applied to the first pyroelectric material and/or the second pyroelectric material. The upper surface of the first pyroelectric material and the lower surface of the second pyroelectric material are surfaces on which a positive charge is generated when the temperature increases, and a negative charge is generated when the temperature decreases. The lower surface of the first pyroelectric material and the upper surface of the second pyroelectric material are surfaces on which a negative charge is generated when the temperature increases, and a positive charge is generated when the temperature decreases.

Touch panel, touch input device, and electronic device

An object of the present invention is to provide a polarized vinylidene fluoride/tetrafluoroethylene copolymer resin film that can significantly reduce, when used as an optical film, the deterioration of the quality of video or still images formed by display elements. The present invention provides a polarized vinylidene fluoride/tetrafluoroethylene copolymer resin film having 2,000 or fewer spot defects per m, the number of spot defects being measured by a defect measurement method;

Method and apparatus for producing a polarized resin film

An object of the present invention is to provide a polarized vinylidene fluoride/tetrafluoroethylene copolymer resin film that can significantly reduce, when used as an optical film, the deterioration of the quality of video or still images formed by display elements. The present invention provides a polarized vinylidene fluoride/tetrafluoroethylene copolymer resin film having 2,000 or fewer spot defects per m, the number of spot defects being measured by a defect measurement method; the method using an surface inspection system in which a CCD camera is placed so as to detect defects at an angle of 45 degrees relative to an LED source, defects of the film are read within a rectangular range of 300 mm in a width direction (the direction perpendicular to the scanning direction), and 150 mm in a machine direction (the scanning direction), while the film is scanned under the camera at a rate of 20 m/min; wherein first, defects having a bright area of 1.5 mmor less and a dark area of 1.4 mmor less are selected; and next, in order to remove defects resulting from causes other than a corona treatment contained in these defects, a circumscribed rectangle of defect is set so as to have two sides along the scanning direction, and the number of only defects that have a circumscribed width of 2.88 mm or less, a circumscribed length of 2.3 mm or less, an aspect ratio of &#x2212;39 to +27, an occupancy area ratio in the circumscribing rectangle of 4,000 to 6,950, and an area ratio of &#x2212;3,100 to +5,200, is automatically counted as spot defects by the surface inspection system.

Polarized resin film and process for producing same

A transparent piezoelectric sheet-with-a-frame includes a transparent piezoelectric sheet and a frame covering a peripheral edge portion of the transparent piezoelectric sheet. The transparent piezoelectric sheet includes one transparent piezoelectric film including an organic polymer, one first transparent plate electrode placed on a first main surface of the transparent piezoelectric film and having a first transparent plate electrode portion, and one second transparent plate electrode placed on a second main surface of the transparent piezoelectric film and having a second transparent plate electrode portion. An outline of the second transparent plate electrode portion is positioned inside an outline of the first transparent plate electrode portion as seen in a plan view. The outline of the first transparent plate electrode portion completely coincides with the frame, and the outline of the second transparent plate electrode portion does not at all coincide with the frame as seen in the plan view.

Transparent piezoelectric sheet-with-A-frame, touch panel, and electronic device each having the transparent piezoelectric sheet

A transparent piezoelectric sheet includes a quadrilateral-shaped transparent piezoelectric film and a first transparent plate electrode. The quadrilateral-shaped transparent piezoelectric film includes an organic polymer. The quadrilateral-shaped transparent piezoelectric film has entire main surfaces that are piezoelectric. The first transparent plate electrode is layered on part of a first main surface of the main surfaces of the transparent piezoelectric film. One to three sides of the four sides of the quadrilateral shape of the transparent piezoelectric film and area(s) of the first main surface adjacent thereto are not covered by the first transparent plate electrode.

Transparent piezoelectric sheet, and transparent piezoelectric sheet-with-a-frame, touch panel, and electronic device each having the transparent piezoelectric sheet

A vinylidene fluoride homopolymer represented by the formula (4):CF-(A)-I&#x2003;&#x2003;(4)wherein Arepresents a structural unit of vinylidene fluoride homopolymer which includes crystal form I alone or as main component and has a number average degree of polymerization of 5 to 12.

Method of forming thin film

There is provided a method of forming a thin film of vinylidene fluoride homopolymer having crystal form I which is applicable to various substrates in relatively easy way (coating conditions, application method, etc.), a process for preparing a vinylidene fluoride homopolymer having crystal form I efficiently at high purity, and novel vinylidene fluoride homopolymers which can give a thin film being excellent in ferroelectricity. The method of forming a thin film of vinylidene fluoride homopolymer comprises (i) a step for preparing a green powder product of vinylidene fluoride homopolymer comprising crystal form I alone or as main component by subjecting vinylidene fluoride to radical polymerization in the presence of a bromine compound or iodine compound having 1 to 20 carbon atoms which contains at least one moiety represented by &#x2014;CRfRfX, wherein X. is iodine atom or bromine atom; Rf. and Rf. are the same or different and each is selected from fluorine atom or perfluoroalkyl groups having 1 to 5 carbon atoms and (ii) a step for forming a thin film on a substrate surface by using vinylidene fluoride homopolymer which comprises crystal form I alone or as main component and is obtained from the green powder product of vinylidene fluoride homopolymer comprising crystal form I alone or as main component.

The present invention provides a process for easily preparing a vinylidene fluoride homopolymer comprising an I-form crystal structure at high purity by selecting a solvent, and the process for preparing the vinylidene fluoride homopolymer comprises not less than 70% by mass of I-form crystal structure, which is obtained by dissolving a vinylidene fluoride homopolymer having a number average degree of polymerization of 3 to 20 in a solvent consisting of an organic solvent having a dipole moment of not less than 2.8 alone or comprising the organic solvent in a part, thereafter, evaporating the solvent.

Growing community of inventors

Settsu, Japan

Tetsuhiro Kodani